subroutine init_output_param
  use output_param
  implicit none

  ! initialize output flags
  print_spatial_dist=.false.
  print_time_evol=.false.
  print_dpa_evol=.false.
  print_reaction_rate=.false.
  print_all_position=.false.

  ! null file name
  psfn=""
  ptfn=""
  pdfn=""
  prfn=""
  ppfn=""

  return

end subroutine init_output_param
